Generally known is a cardboard carton which is filled up with granular materials such as powdered detergents for containing the same. Such a cardboard carton is made of cardboard which is prepared from laminated synthetic resin or the like, to allow no permeation of moisture etc. The cardboard carton is generally provided with a box which is filled up with the granular materials, and a lid for closing an opening portion of the box. When the lid is attached to one side of the box, the lid is disadvantageously semi-opened by the elastic force of the cardboard when force for pressing the lid against the opening of the box is relieved, due to the elasticity of the cardboard.
In order to solve this problem, a locking tongue member is provided on an upper portion of a front panel of a box, as disclosed in U.S. Pat. No. 5,161,734, so that this locking tongue member and a locking recess which is formed in a from flap of a lid are shaped to be engageable with each other. According to this method, it is possible to lock the lid by inserting the locking tongue member in the locking recess.
FIG. 17 is a perspective view showing a conventional cardboard carton employing such a locking method. Referring to FIG. 17, a box 1 is in the form of a square box which is provided with an opening in its upper portion, and has a front panel 2, a back panel 3 and side panels 4 and 5. The box 1 is filled up with granular materials such as powdered detergents, and a sealing paper 6 serving as a sealing member is applied to the opening of the box 1. A lid 10 is attached to an upper portion of the back panel 3 of the box 1. The lid 10 is provided with a front flap 11 and side flaps 12 and 13 for covering the upper portions of the front panel 2 and the side panels 4 and 5 upon closure of the lid 10.
A locking tongue member 7 is provided on the upper portion of the front panel 2 of the box 1. On the other hand, a locking recess 1a is formed in an inner side of the front flap 11 of the lid 10, along the shape of the locking tongue member 7. This locking recess 11a is formed by applying auxiliary flaps 12a and 13a continuously extending from the side flaps 12 and 13 to the rear side of the front flap 11. A handle 15 which is made of synthetic resin or the like is attached to the upper portion of the box 1 through rivets 16 which are mounted on the side panels 4 and 5. An adhesive seal 17 is applied to the front flap 11 and the from panel 2 in a closed state of the lid 10, and generally removed when use of the carton is started.
When the lid 10 is closed, the locking tongue member 7 which is provided on the upper portion of the front panel 2 engages in the locking recess 11a provided in the inner side the lid 10, for locking the lid 10. Thus, the lid 10 is held in the closed state. The locking tongue member 7 is rotatable about a base portion on which the same is mounted. When the lid 10 is pushed up with slight force, therefore, the locking tongue member 7 is raised up to release the lid 10 from the locking state, so that the same can be opened.
The aforementioned conventional cardboard carton has the following problems:
When the consumer first opens the lid 10 after purchasing the carton, the sealing paper 6 is applied onto the box 1 and the locking tongue member 7 frontwardly projects in the state shown in FIG. 17. While it is necessary to separate the sealing paper 6 in the first place in order to take out the granular materials from the box 1, the consumer may erroneously recognize the locking tongue member 7, frontwardly projecting from a portion is under the sealing paper 6, as a tab for separating the sealing paper 6, to raise up and tear off the locking tongue member 7. When the locking tongue member 7 is thus removed, the locking mechanism for the lid 10 becomes inoperative.
Further, in a step of manufacturing the cardboard canon by filling up the same with the granular materials, while the sealing paper 6 is applied to the opening after the box 1 is filled up with the granular materials, the frontwardly projecting locking tongue member 7 is also glued and the sealing paper 6 cannot be applied in a normal state. When the sealing paper 6 is applied to the portion of the locking tongue member 7, the forward portion of the sealing paper 6 floats to readily define a clearance. When such a clearance is defined, the granular materials which is contained in the carton disadvantageously spills out to the exterior.
Due to such a projecting state of the locking tongue member 7, further, it is difficult to mechanically fill up the box 1 with the granular materials.
Therefore, an object of the present invention is to solve the aforementioned problems of the prior art and provide a cardboard carton which can prevent a consumer from erroneously separating a locking tongue member with a sealing paper, and suitable for mechanical filling of the content and capable of applying the sealing paper to a proper position in manufacturing steps.